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https://github.com/coreutils/coreutils.git
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Use more-consistent rules among cp, ln, and mv when dealing with
last operands that are (or look like) directories. * src/cp.c (target_directory_operand): New, nearly-common function, It reports an error if the destination appears to be a directory (e.g., because it has a trailing slash) but is not. * src/ln.c, src/mv.c: Likewise. * src/cp.c (do_copy): Use it. * src/ln.c (main): Likewise. * src/mv.c (main): Likewise. * src/cp.c (do_copy): Don't output a usage message because of file problems (e.g., an operand is not a directory). Use it only for syntax. Standardize on "target %s is not a directory" for the diagnostic. * src/ln.c (main): Likewise. * src/mv.c (main): Likewise. * src/cp.c (do_copy): Remove test for trailing slash, since target_directory_operand now does this. * src/ln.c (main): Likewise. * src/mv.c (movefile): Likewise. * src/cp.c (main): Reject multiple target directories. Check whether a specified target is a directory when parsing the options, using stat. This gives more-accurate diagnostics. * src/ln.c (main): Likewise. * src/ln.c (isdir): Remove decl; no longer needed. * src/mv.c (isdir, lstat): Likewise. * src/ln.c (do_link): New arg dest_is_dir. All uses changed. Don't check the destination ourself; rely on dest_is_dir. This way we can avoid lstatting the destination in the usual case, and in the worst case we lstat 1, not 3 times. Don't bother to unlink unless link failed; this saves a syscall. Remove unnecessary backup_succeeded flag; it was identical to "dest_backup != NULL". * src/ln.c (main): Use int to count to argc, not unsigned int. This handles negative operand counts. * src/mv.c (main): Likewise.
This commit is contained in:
Jim Meyering
parent
8340545c8b
commit
59c3b53926
209
src/ln.c
209
src/ln.c
@ -87,8 +87,6 @@ int symlink ();
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} \
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while (0)
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int isdir ();
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/* The name by which the program was run, for error messages. */
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char *program_name;
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@ -140,19 +138,40 @@ static struct option const long_options[] =
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{NULL, 0, NULL, 0}
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};
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/* FILE is the last operand of this command. Return true if FILE is a
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directory. But report an error there is a problem accessing FILE,
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or if FILE does not exist but would have to refer to an existing
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directory if it referred to anything at all. */
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static bool
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target_directory_operand (char const *file)
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{
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char const *b = base_name (file);
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size_t blen = strlen (b);
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bool looks_like_a_dir = (blen == 0 || ISSLASH (b[blen - 1]));
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struct stat st;
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int err = ((dereference_dest_dir_symlinks ? stat : lstat) (file, &st) == 0
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? 0 : errno);
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bool is_a_dir = !err && S_ISDIR (st.st_mode);
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if (err && err != ENOENT)
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error (EXIT_FAILURE, err, _("accessing %s"), quote (file));
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if (is_a_dir < looks_like_a_dir)
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error (EXIT_FAILURE, err, _("target %s is not a directory"), quote (file));
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return is_a_dir;
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}
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/* Make a link DEST to the (usually) existing file SOURCE.
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Symbolic links to nonexistent files are allowed.
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If DEST is a directory, put the link to SOURCE in that directory.
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If DEST_IS_DIR, put the link to SOURCE in the DEST directory.
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Return 1 if there is an error, otherwise 0. */
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static int
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do_link (const char *source, const char *dest)
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do_link (const char *source, const char *dest, bool dest_is_dir)
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{
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struct stat source_stats;
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struct stat dest_stats;
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char *dest_backup = NULL;
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int lstat_status;
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int backup_succeeded = 0;
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int lstat_status = -1;
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/* Use stat here instead of lstat.
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On SVR4, link does not follow symlinks, so this check disallows
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@ -182,33 +201,16 @@ do_link (const char *source, const char *dest)
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}
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}
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lstat_status = lstat (dest, &dest_stats);
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if (lstat_status != 0 && errno != ENOENT)
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if (dest_is_dir)
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{
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error (0, errno, _("accessing %s"), quote (dest));
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return 1;
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}
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/* If the destination is a directory or (it is a symlink to a directory
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and the user has not specified --no-dereference), then form the
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actual destination name by appending base_name (source) to the
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specified destination directory. */
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if ((lstat_status == 0
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&& S_ISDIR (dest_stats.st_mode))
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#ifdef S_ISLNK
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|| (dereference_dest_dir_symlinks
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&& (lstat_status == 0
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&& S_ISLNK (dest_stats.st_mode)
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&& isdir (dest)))
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#endif
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)
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{
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/* Target is a directory; build the full filename. */
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/* Treat DEST as a directory; build the full filename. */
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char *new_dest;
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PATH_BASENAME_CONCAT (new_dest, dest, source);
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dest = new_dest;
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}
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/* Get stats for new DEST. */
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if (remove_existing_files || interactive || backup_type != none)
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{
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lstat_status = lstat (dest, &dest_stats);
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if (lstat_status != 0 && errno != ENOENT)
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{
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@ -256,11 +258,6 @@ do_link (const char *source, const char *dest)
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if (!yesno ())
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return 0;
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}
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else if (!remove_existing_files && backup_type == none)
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{
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error (0, 0, _("%s: File exists"), quote (dest));
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return 1;
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}
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if (backup_type != none)
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{
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@ -282,20 +279,6 @@ do_link (const char *source, const char *dest)
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else
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dest_backup = NULL;
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}
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else
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{
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backup_succeeded = 1;
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}
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}
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/* Try to unlink DEST even if we may have renamed it. In some unusual
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cases (when DEST and DEST_BACKUP are hard-links that refer to the
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same file), rename succeeds and DEST remains. If we didn't remove
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DEST in that case, the subsequent LINKFUNC call would fail. */
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if (unlink (dest) && errno != ENOENT)
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{
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error (0, errno, _("cannot remove %s"), quote (dest));
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return 1;
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}
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}
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@ -305,7 +288,7 @@ do_link (const char *source, const char *dest)
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? _("create symbolic link %s to %s")
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: _("create hard link %s to %s")),
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quote_n (0, dest), quote_n (1, source));
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if (backup_succeeded)
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if (dest_backup)
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printf (_(" (backup: %s)"), quote (dest_backup));
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putchar ('\n');
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}
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@ -315,6 +298,36 @@ do_link (const char *source, const char *dest)
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return 0;
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}
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/* If the attempt to create a link failed and we are removing or
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backing up destinations, unlink the destination and try again.
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POSIX 1003.1-2004 requires that ln -f A B must unlink B even on
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failure (e.g., when A does not exist). This is counterintuitive,
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and we submitted a defect report
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<http://www.opengroup.org/sophocles/show_mail.tpl?source=L&listname=austin-review-l&id=1795>
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(2004-06-24). If the committee does not fix the standard we'll
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have to change the behavior of ln -f, at least if POSIXLY_CORRECT
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is set. In the meantime ln -f A B will not unlink B unless the
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attempt to link A to B failed because B already existed.
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Try to unlink DEST even if we may have backed it up successfully.
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In some unusual cases (when DEST and DEST_BACKUP are hard-links
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that refer to the same file), rename succeeds and DEST remains.
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If we didn't remove DEST in that case, the subsequent LINKFUNC
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call would fail. */
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if (errno == EEXIST && (remove_existing_files || dest_backup))
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{
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if (unlink (dest) != 0)
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{
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error (0, errno, _("cannot remove %s"), quote (dest));
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return 1;
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}
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if (linkfunc (source, dest) == 0)
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return 0;
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}
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error (0, errno,
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(symbolic_link
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? _("creating symbolic link %s to %s")
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@ -404,10 +417,8 @@ main (int argc, char **argv)
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char *backup_suffix_string;
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char *version_control_string = NULL;
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char *target_directory = NULL;
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int target_directory_specified;
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unsigned int n_files;
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int n_files;
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char **file;
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int dest_is_dir;
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initialize_main (&argc, &argv);
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program_name = argv[0];
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@ -469,6 +480,17 @@ main (int argc, char **argv)
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#endif
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break;
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case TARGET_DIRECTORY_OPTION:
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if (target_directory)
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error (EXIT_FAILURE, 0, _("multiple target directories specified"));
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else
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{
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struct stat st;
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if (stat (optarg, &st) != 0)
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error (EXIT_FAILURE, errno, _("accessing %s"), quote (optarg));
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if (! S_ISDIR (st.st_mode))
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error (EXIT_FAILURE, 0, _("target %s is not a directory"),
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quote (optarg));
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}
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target_directory = optarg;
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break;
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case 'v':
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@ -486,33 +508,24 @@ main (int argc, char **argv)
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}
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}
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if (argc <= optind)
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n_files = argc - optind;
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file = argv + optind;
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if (n_files <= 0)
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{
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error (0, 0, _("missing file operand"));
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usage (EXIT_FAILURE);
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}
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n_files = argc - optind;
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file = argv + optind;
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target_directory_specified = (target_directory != NULL);
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if (!target_directory)
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target_directory = file[n_files - 1];
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/* If target directory is not specified, and there's only one
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file argument, then pretend `.' was given as the second argument. */
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if (!target_directory_specified && n_files == 1)
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{
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static char *dummy[2];
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dummy[0] = file[0];
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dummy[1] = ".";
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file = dummy;
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n_files = 2;
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dest_is_dir = 1;
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}
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else
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{
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dest_is_dir = isdir (target_directory);
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if (n_files < 2)
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target_directory = ".";
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else if (2 <= n_files && target_directory_operand (file[n_files - 1]))
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target_directory = file[--n_files];
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else if (2 < n_files)
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error (EXIT_FAILURE, 0, _("target %s is not a directory"),
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quote (file[n_files - 1]));
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}
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if (symbolic_link)
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@ -520,13 +533,6 @@ main (int argc, char **argv)
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else
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linkfunc = link;
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if (target_directory_specified && !dest_is_dir)
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{
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error (0, 0, _("%s: specified target directory is not a directory"),
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quote (target_directory));
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usage (EXIT_FAILURE);
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}
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if (backup_suffix_string)
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simple_backup_suffix = xstrdup (backup_suffix_string);
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@ -534,51 +540,14 @@ main (int argc, char **argv)
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? xget_version (_("backup type"), version_control_string)
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: none);
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if (target_directory_specified || n_files > 2)
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if (target_directory)
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{
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unsigned int i;
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unsigned int last_file_idx = (target_directory_specified
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? n_files - 1
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: n_files - 2);
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if (!target_directory_specified && !dest_is_dir)
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error (EXIT_FAILURE, 0,
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_("when making multiple links, last argument must be a directory"));
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for (i = 0; i <= last_file_idx; ++i)
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errors += do_link (file[i], target_directory);
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int i;
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for (i = 0; i < n_files; ++i)
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errors |= do_link (file[i], target_directory, true);
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}
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else
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{
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struct stat source_stats;
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char const *source = file[0];
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char *dest = file[1];
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size_t destlen = strlen (dest);
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char *new_dest = dest;
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/* When the destination is specified with a trailing slash and the
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source exists but is not a directory, convert the user's command
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`ln source dest/' to `ln source dest/basename(source)'.
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However, skip this step if dest/basename(source) is a directory. */
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if (destlen != 0
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&& dest[destlen - 1] == '/'
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&& lstat (source, &source_stats) == 0
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&& !S_ISDIR (source_stats.st_mode))
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{
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struct stat dest_stats;
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char *dest_plus_source_basename;
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PATH_BASENAME_CONCAT (dest_plus_source_basename, dest, source);
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if (! ((((dereference_dest_dir_symlinks ? stat : lstat)
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(dest_plus_source_basename, &dest_stats))
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== 0)
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&& S_ISDIR (dest_stats.st_mode)))
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new_dest = dest_plus_source_basename;
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}
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errors = do_link (source, new_dest);
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}
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errors = do_link (file[0], file[1], false);
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exit (errors == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
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}
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